Field of the Invention
The present invention relates to an imaging device and an imaging system.
Description of the Related Art
In a single-plate-type imaging device, color filters (CF) through which specific wavelength components, for example, lights of respective colors of red (R), green (G), and blue (B) pass are arranged in a particular pattern on pixels in order to obtain a color image. As a CF pattern, those having a so-called Bayer arrangement are widely used. Further, in addition to a CF of RGB, there is a growing use of a CF of an RGBW arrangement that includes W pixels having a filter that transmits light in the entire wavelength range of visible light. While a CF of the RGBW arrangement can improve the detection sensitivity by using the W pixel, the density of RGB pixels is lower than other CF arrangements such as a Bayer arrangement, and thus there is a problem of false color being likely to occur.
International Publication No. WO2013/161349 discloses an image processing device and an image processing method for reducing the influence of false color that occurs when a high-luminance light locally enters an imaging device having a CF of the RGBW arrangement.
Generally, a demosaicing process of pixels of the RGBW arrangement is performed based on the ratio of pixel values of RGB pixels and W pixels. The ratio of the pixel values of the RGB pixels and the W pixels here is ideally constant regardless of the luminance. In practice, however, a lower luminance of an incident light results in a larger error from the ideal value due to an offset component of pixels, random noise, or the like, and such an error causes the false color.